The present invention broadly relates to composite electroplated articles and to a process for producing such articles provided with a composite electroplate thereover providing corrosion protection and a decorative finish to the substrate. More particularly, the present invention comprises a further improvement over a composite nickel-iron electroplated article and process as described in U.S. Pat. No. 3,994,694, granted Nov. 30, 1976. In accordance with the aforementioned United States patent, improved corrosion protection, durability and appearance are accomplished by electrodepositing on a conductive substrate, a plurality of layers of a nickel-iron alloy the inner layer of which is of a relatively high iron content while the adjacent outer layer is of a relatively lower iron content. In accordance with a preferred embodiment of the foregoing patent, a nickel-containing plate is applied on the outer nickel-iron alloy plate over which a decorative chromium plate or equivalent decorative plate is applied.
While the composite nickel-iron electroplated structure of the aforementioned U.S. patent has provided for substantially improved corrosion resistance and durability when subjected to outdoor exposure during service, such as to automotive service conditions in the form of decorative trim components, the imposition of still more stringent specifications for corrosion resistance and cosmetic defects has created a need for still further improvements in the performance of such composite nickel-iron electroplates.
In accordance with the present invention, a composite electroplated article and process for producing such article is provided which is particularly applicable for protecting basis metals such as steel, copper, brass, aluminum and zinc die castings which are subject to outdoor exposure during service, particularly to automotive service conditions. Beneficial results and corrosion protection are also achieved by the application of such composite electrodeposits on plastic substrates which have been subjected to suitable pretreatments in accordance with well-known techniques to provide an electrically conductive surface such as copper layer rendering the plastic substrate receptive to nickel electroplating. Plastics incorporating conductive fillers to render them platable can also advantageously be processed in accordance with the present invention. Typical of plastic materials which can also be electroplated are ABS, polyolefin, polyvinylchloride, and phenol-formaldehyde polymers. The provision of such a composite electroplate on plastic substrates substantially reduces or eliminates cosmetic defects such as "green" corrosion stains produced by a corrosive attack of a copper basis layer or strike on the plastic substrate.
The composite electroplated article and process of the present invention provide for still further improvements in the corrosion protection and durability of electroplated substrates while retaining the advantages of reduced cost by way of employing nickel-iron alloys as the primary electrodeposits in comparison to more costly electrodeposits of substantially pure nickel of composite nickel-electroplated articles in accordance with compositions and processes as disclosed in U.S. Pat. Nos. 3,090,733 and 3,703,448.